Archive for the ‘Toilet Efficiency Series’ Category

How to Select a High Efficiency Toilet (HET)

May 12, 2009 5 comments

Toto ImageBased on all of the toilet talk and analysis in our previous posts on toilet efficiency, Lara and I have come up with a plan that will allow us to reduce the water consumed by the six toilets at our four properties from approximately 49,500 gallons per year to 29,000 gallons per year – a 42% decrease and savings of 20,500 gallons per year. In this post, we’ll look at the specifics of the plan and give you some tips on new toilet selection.

The Plan

Our immediate action plan to save over 20,000 gallons of water per year is as simple as replacing our two old, inefficient toilets with new high efficiency toilets (HET’s). For our own home, we will purchase a Toto Aquia dual flush HET pictured above to replace the existing 3.5 gpf model. The Toto Aquia uses 1.6 gpf to flush solids, 0.9 gpf for liquids. At our rental property where our other offending 3.5 gpf toilet resides, we will go with a 1.28 gpf Toto EcoDrake HET.

For disposal, we’ll take the 3.5 gpf toilets to ReSource to take advantage of a great City of Fort Collins toilet recycling program under which old toilets are collected, crushed and incorporated into road base at no cost to the homeowner to keep them out of the landfill.

Selecting a High Efficiency Toilet

We discovered that researching and deciding which HET to purchase can be a bit overwhelming. Following the four simple steps below will help you keep this process manageable.

1. Start with the EPA’s list of WaterSense® labeled high efficiency toilets. The HET’s on this list have been certified to meet performance criteria developed by the EPA.  Be forewarned, this list is long, with nearly three dozen toilet brands and many models per brand.

2. Develop a short list of HET prospects for further scrutiny. You can do this quickly by using the web to check out prices, styles and colors for the various models on WaterSense® list.

3. Consult the experts to help you make a final decision. Like Step 2, this is easy to accomplish on line by searching for reviews on makes/models on your short list, or you can ask a trusted plumber or green builder you know in your area. We found this site from plumber Terry Love to be particularly helpful.

4. Purchase with eyes wide open. Toilet tanks and bowls are often sold separately. Also, seats and lids are typically not included with the tank and bowl. Some manufacturers do not provide warranty coverage for products purchased over the internet. And then there are some e-tailers who offer attractive prices and promote “free shipping”. Look closely…we found one such claim where shipping was indeed free, but “freight charges” were significant! Finally, be sure to look for incentives, rebates and eco-friendly disposal programs. This is as simple as checking your municipality’s web site.

Here’s how our selection process played out…

Steps 1 and 2 – We quickly shortlisted to three prospects; Toto, Caroma and Kohler. Toto and Caroma made the list because we were aware of them as manufacturers from countries that have long been focused on toilet water conservation (Japan and Australia, respectively) with relatively long track records of HET production. Kohler made our short list simply due to brand name recognition.

Step 3 – Our situation quickly became a Toto vs. Caroma showdown after we discovered several online stories about serious problems with Kohler’s performance, poor customer service and high replacement part costs related to their HET’s. We started leaning toward Toto over Caroma because we liked the styling better, and Maximum Performance Testing (MaP) ratings favored Toto for the models we were comparing (click here to learn more about MaP testing). This thread from Terry Love’s website sealed the deal in favor of Toto. We chose their dual flush Aquia for our own home to maximize water savings, and decided that their EcoDrake was a better choice for our rental property due to ease of operation and lower price point.

Step 4 – We decided to purchase our toilets at Green Logic because we prefer to work with other green-minded local businesses and keep more of the dollars we spend in our community. We are also comforted by the idea that we have someone we can turn to for support with future parts or warranty needs, should they arise.

Flushing Factoid

According to the EPA, if every American home with older, inefficient toilets replaced them with new WaterSense® labeled toilets, we would save nearly 640 billion gallons of water per year, equal to more than two weeks of flow over Niagara Falls!

Are the toilets in your home a part of the problem, or part of the solution?

Toilet Efficiency Case Study – Part 3 – Options and Payback

Toilet Tank BankIn Part 2 of this series, we verified that all four toilets at our two-bathroom rental properties are efficient 1.6 gpf / 6.0 lpf models.  We also determined that we have two 3.5 gpf toilets in need of mitigation – one at our personal residence and one at our one-bathroom rental home.  So we’ve built a spreadsheet model to help us evaluate our water conservation options.

Before we get into the details of the model, let’s look at the two general options we will be evaluating with it – displacement and replacement.


Displacing water in your toilet’s tank is an easy, low-cost way to start saving water immediately.  You can accomplish this by using a product specifically manufactured for this purpose, like the “Toilet Tank Bank” depicted above, which saves 0.8 gallons per flush.  You can also employ a used plastic beverage bottle filled with sand or gravel to keep it submerged in the tank.  Or, as a friend said in a comment about my Facebook feed of Part 1 of this series…”I remember an ecology module in the 6th grade suggested putting a brick in the tank for water displacement”.   Yup, that can work too.


Upcycling plastic bottles or bricks is definitely a green, no-cost way to go.  However, we think the Toilet Tank Bank is the better approach.  Practically speaking, it will take a challenging combination of bottles or bricks to equal or exceed the tank bank’s 0.8 gpf of displacement.  This could interfere with the toilet’s flapper function, causing leaking that far offsets any savings achieved. 

The Toilet Tank Bank will cost you about $2.  It is readily available from a wide range of e-tailers.  Watch the shipping charges…maybe you can add a low-flow showerhead or other water-conserving item to your order to reach the minimum purchase amount for free shipping and achieve goodness all the way around.


From a water conservation perspective, toilets can be classified as good, better and best.  Efficient toilets labeled 1.6 gpf / 6.0 lpf are good compared to their 3.5 to 7.0 gpf predecessors.  High Efficiency Toilets, or HET’s, offer 20% better conservation at 1.28 gpf.  And Dual Flush HET’s offer the best water conservation with a 1.28 gpf flush option for solids, and a 0.8 gpf option for liquids. 

The Model

We’ve modeled some mitigation scenarios for the two 3.5 gpf toilets at our Sunset Avenue and Buckeye Street properties (see the figure below for scenarios and results).  If you have a Google account and would like to access this tool for your own scenario testing, just click on the figure to access it in Google Docs spreadsheet format.  Please be sure to follow the instructions in red that tell you how to save a copy before modifying the spreadsheet.  If you don’t have a Google account, you’ll need to set one up (self explanatory at 

Any difficulties? Contact us and we’ll get the spreadsheet to you by email.

Applying the Tool to Our Inefficient Toilets

If you are motivated to save as much water as possible, and you can afford to spend $300 or more per toilet, you should give serious consideration to a dual flush model.  As the spreadsheet shows, installing a dual flush high efficiency toilet will reduce the annual water consumption at our Buckeye Street residence by over 9,500 gallons.  This is almost 28% of our household’s total water consumption of 34,500 gallons per year! 

If cost and payback period considerations trump maximizing water conservation in your mind, and your inefficient toilet looks and works fine, a Toilet Tank Bank is a good mitigation option.  We installed one in the toilet in our home immediately after measuring its 3.5 gpf water consumption.  This simple, low-cost effort will reduce our average monthly household water consumption by 8% from approximately 3,000 gallons per month to 2,760 until we can research, decide upon and install a high efficiency toilet.

If you are planning to replace your toilet anyway and are pondering toilets of differing efficiency, you can use this model to do a comparative analysis.  Input the less efficient of the two toilets to be compared as “existing toilet data”, input the more efficient as “modified or new toilet data”, and input the difference in cost as “cost to modify or buy new toilet”.  The resulting calculations will tell you the comparative savings and payback period for choosing the more efficient toilet.

OK, enough toilet talk for this installment.  We hope you will tune in to Part 4 where we’ll summarize our research into specific models of high efficiency toilets, and tell you what the plan is for replacing our 3.5 gpf toilets.

Toilet Efficiency Case Study – Part 2 – How to Measure Flush Volume and Leak Test

April 4, 2009 1 comment

Women's toiletAs promised in our previous post on toilet efficiency, we’ve inventoried the six toilets at our home and three investment properties.  Now, we’ll show you how to leak test your toilet and determine its flush volume in gallons per flush, and we’ll summarize the data for our toilets. 

Determining Flush Volume

If you live in a home that was built before The Energy Policy Act of 1992 (United States) took effect in 1994, and have not replaced your toilet, it probably has a wasteful flush volume ranging anywhere from 3.5 to 7.0 gallons per flush (gpf). 

If you don’t know the flush volume of your toilet, and you don’t see “1.6 GPF” printed right behind the seat on the bowl (along with the equivalent “6.0 LPF” for litres per flush), there is an easy way to determine it. 

You’ll need a gallon jug or bucket.  With that in hand, just follow the five easy steps at this link from the Marin Municipal Water District to determine your toilet’s gallons per flush (gpf).  Or, follow our step by step video below.

Checking for Leaks

Leak testing is as easy as coloring the water in your toilet’s tank with something safe like food coloring, waiting for a half hour, and then checking to make sure that none of the coloring has shown up in the toilet bowl.  See Toiletology 101 for more details on testing, significance of leaks, and how to fix them if you find them.  

Data for Our Toilets

  • Phoenix Street Property – two 1.6 gpf toilets manufactured by VitrA, neither leak.
  • Maple Street Property – two 1.6 gpf toilets, one manufactured by Fremont and one by VitrA, neither leak.
  • Sunset Avenue Property – one very old toilet, brand obscure, measured flow = 3.5 gpf, does not leak.
  • Buckeye Street Property (our residence) – one Crane toilet, 3.5 gpf, does not leak.

So now we’ve got the data we need to build a tool that will allow us to determine our current toilet water consumption, estimate water conservation associated with various modification/replacement scenarios, and calculate payback times. 

In Part 3, we’ll present and discuss this tool, and make it available for you to use for your own assessment.

Until then, it is worth reading and thinking about this piece on Peak Water from Twilight Earth.  It may increase your sense of urgency (pun intended) to tackle toilet efficiency and other water conservation measures, regardless of what we learn about projected payback times in Part 3.

Thanks gromgull for the cool toilet image.



Tackle Your Toilets to Save Water and Money – A Case Study – Part 1

publication1Lara and I are the proud owners of six toilets at our four properties – one at our personal residence and five at three rental properties.  That’s a troublesome amount of flushes every day for which we’re directly and indirectly responsible.  Why worry?  Because a 1999 study by the American Water Works Association found that the toilet can account for nearly 27% of indoor water usage, and that figure may even exceed 40% if the toilet leaks. 


With evermore frequent stories about the water woes in our state of Colorado, and the U.S. EPA indicating that 35 other states expect to experience local, regional, or statewide water shortages in 5 years or less, it has become clear that we (and you?) are long overdue for a comprehensive toilet water consumption study and reduction plan (sounds like an EPA report title itself).


We know from intimate experience that the “necessary” fixture in our personal residence is not a water-efficient toilet.  In fact, we currently employ a method of toilet water conservation true to our cabin-country septic system Minnesota roots that would even make Garrison Keillor proud: the proverbial “…if it’s yellow, let it mellow…”


I know, TMI.


Our recollection of the toilet situation at the rental properties is not so intimate, and actually a bit sketchy.  We are pretty sure that we replaced the four original toilets at both two-bathroom rental properties four or five years ago with more efficient 1.6 gallons per flush (gpf) models. And we hope that we’ve done the same at our one-bathroom rental, but honestly can’t recall for sure.  Time and busyness have clouded our memory. 


So we’ve contacted all of our tenants and tomorrow evening we’ll make the rounds, with measuring equipment and food coloring in hand, to do a toilet consumption and leak test inventory.  They’ll think we’re odd of course, but since they are responsible for paying the utilities, they’ll find our oddness in their interest, if not endearing.


We’ll report back shortly with measurement methods, THE DATA, water consumption reduction options, and calculated water savings and return-on-investment scenarios, so stay tuned for the next installment of this case study.  


Until then, flush softly and carry a big plunger…